The fabrication of integrated circuits generally involves the use of a number of masking steps for patterning and etching different parts of components for the integrated circuits. Each masking step is relatively expensive. Thus, for integrated circuits requiring a large number of masking steps, the process for fabricating those integrated circuits can be very expensive.
For conventional integrated circuits including multi-level metal stacks, the fabrication process generally provides for forming a metal line, forming an insulating layer, etching vias in the insulating layer, filling the vias to form contacts, and forming a next metal line. The process is repeated until the desired number of metal lines is formed. Thus, contacts are formed from the top of each metal line to the bottom of a subsequently formed metal line. This process requires a relatively large number of masking steps for metal stacks having more than just a few metal lines, making the process relatively expensive to implement.